Method of calibrating an apparatus for producing a three-dimensional object, calibration apparatus and method and apparatus for producing a three-dimensional object

Abstract

The invention refers to a method for calibrating the control of a radiation device producing electromagnetic radiation or particle radiation in a rapid prototyping system. The method comprises the steps of arranging a calibration plate at a defined position in the rapid prototyping system, the calibration plate having an upper side with a first region and a second region separate from the first region, the first region being provided with optically detectable reference marks and the second region having a medium which is sensitive to the radiation of the radiation device, producing a test pattern by exposing said medium to said radiation at predetermined desired positions defined by position coordinate data, digitizing the first region of the calibration plate with the reference marks thereon and the second region of the calibration plate having the test pattern, comparing the digitized reference marks and the digitized test pattern and calculating and providing correction data for the control of the radiation device on the basis of the comparison.

What is claimed is:  
     
       1. A method of calibrating an apparatus for producing a three-dimensional object by solidifying a material in subsequent layers of said object at places corresponding to cross-sections of said object in said layers using a focused beam of a radiation solidifying said material, said object being built on a plate defining an invariable coordinate system which is fixed relative to said apparatus, 
       said method comprising the steps of  
       a) providing detectable reference features on said plate for calculating said coordinate system,  
       b) operating control means for deflecting said focused radiation beam to predetermined desired positions in said coordinate system,  
       c) detecting the actual positions of said deflected radiation beam on said plate,  
       d) determining the deviations of said actual positions from said desired positions on the basis of said reference features, and  
       e) adjusting said control means on the basis of said determined deviations.  
     
     
       2. The method of  claim 1 , comprising the further steps of 
       locating a calibration apparatus at a predetermined position in a machine coordinate system, the calibration apparatus having a first region comprising optically detectable reference features and a second region comprising a medium which is sensitive to said radiation of said focused beam,  
       generating a test pattern by exposing said medium to said radiation at predetermined desired positions on the basis of position coordinates,  
       digitizing said first region of said calibration apparatus comprising said reference features and said second region of said calibration apparatus comprising said test pattern,  
       comparing said digitized reference features with said digitized test pattern and  
       calculating and providing correction data for said control means on the basis of said comparison.  
     
     
       3. The method of  claim 2 , wherein said calibration apparatus is a calibration plate. 
     
     
       4. The method of  claim 2 , wherein said first region is located aside of or below said second region. 
     
     
       5. The method of  claim 2 , comprising using a plurality of adjustment crosses for said test pattern, the crossing points of said adjustment crosses forming a coordinate grid. 
     
     
       6. A method of producing a three-dimensional object, comprising 
       providing a plate having reference marks defining an invariable machine coordinate system,  
       forming subsequent layers of a material on said plate, said material being solidifiable by a focused radiation beam,  
       scanning a focused radiation beam across said layers for solidifying said material at places corresponding to cross-sections of said object in said layers, and  
       treating or applying said solidified object in a following processing step whereby said solidified object is aligned and/or treated using said reference marks of said plate.  
     
     
       7. Calibration apparatus for calibrating a radiation device of an apparatus for producing a three-dimensional object by solidifying a material in subsequent layers at places corresponding to cross-sections of said object in said layers using a focused beam of a radiation solidifying said material, said layers being formed on a plate defining a machine coordinate system which is fixed relative to said apparatus, 
       said calibration apparatus comprising  
       a first region having optically detectable reference marks,  
       a second region provided with a medium which is sensitive to said radiation of said focused beam, and  
       adjustment means for positioning said calibration apparatus at a defined position in said machine coordinate system.  
     
     
       8. The calibration apparatus of  claim 7 , comprising a calibration plate. 
     
     
       9. The calibration apparatus of  claim 8 , said medium comprising a radiation-sensitive film pasted onto the upper side of said calibration plate. 
     
     
       10. The calibration apparatus of  claim 7 , wherein said reference marks are arranged along two lines including an angle of preferably 90° therebetween. 
     
     
       11. An apparatus for producing a three-dimensional object by solidifying a material in subsequent layers of said object at places corresponding to cross-sections of said object in said layers, using a focused beam of a radiation solidifying said material, said apparatus comprising 
       carrier means defining a machine coordinate system which is fixed relative to said apparatus,  
       radiation means delivering said focused radiation beam, and  
       calibration means arranged on said carrier means at a defined position in said machine coordinate system, said calibration means having a first region with optically detectable reference marks and a second region provided with a medium which is sensitive to said focused radiation beam of said radiation means.  
     
     
       12. A method of producing a three-dimensional object, comprising 
       providing a plate having reference features thereon defining an invariable machine coordinate system,  
       reading geometrical data defining said object in an object coordinate system,  
       aligning said object coordinate system to said machine coordinate system,  
       forming subsequent layers of a material on said plate, said material being solidifiable by a focused radiation beam, and  
       scanning a focused radiation beam across said layers for solidifying said material at places corresponding to cross-sections of said object in said layers to thereby form said object on said plate.